Strain assisted spin torque switching spin transfer torque memory
Described is an apparatus which comprises: a magnetic tunneling junction (MTJ) having a free magnetic layer; a piezoelectric layer; and a conducting strain transfer layer coupled to the free magnetic layer and the piezoelectric layer. Described is a method, which comprises: exciting a piezoelectric layer with a voltage driven capacitive stimulus; and writing to a MTJ coupled to the piezoelectric layer via a strain assist layer. Described is also an apparatus which comprises: a transistor; a conductive strain transfer layer coupled to the transistor; and a MTJ device having a free magnetic layer coupled to the conductive strain transfer layer.
1. An apparatus comprising:
a magnetic junction including a free magnetic layer;
a first layer comprising piezoelectric material; and
a second layer with conductive strain transfer, wherein the second layer is coupled to the free magnetic layer and the piezoelectric layer, wherein the second layer includes one of: W, Cu, Nb, or STO (StTiO 3 ).
2. The apparatus of claim 1 comprises:
a first electrode coupled to the magnetic junction;
a second electrode coupled to the conductive strain transfer layer; and
a third electrode coupled to the first layer.
3. The apparatus of claim 2 comprises:
a first bit-line for coupling to the first electrode;
a source line for coupling to the second electrode; and
a second bit-line for coupling to the third electrode.
4. The apparatus of claim 3 , wherein:
the first bit-line is disposed on a fourth metal line layer,
the second bit-line is disposed on the second metal line layer, and
the source line is disposed on the zero metal line layer.
5. The apparatus of claim 4 , wherein the magnetic junction is positioned in a region for the second metal line layer.
6. The apparatus of claim 3 , wherein:
the first bit-line is disposed on a fourth metal line layer,
the second bit-line is disposed on the sixth metal line layer, and
the source line is disposed on the second metal line layer.
7. The apparatus of claim 3 comprises:
a first transistor coupled to the source line and the second electrode, wherein the first transistor is to couple the source line to the second electrode according to a voltage potential of a select line.
8. The apparatus of claim 7 comprises:
a second transistor coupled to the third electrode and the second bit-line, wherein the second transistor is to couple the second bit-line to the third electrode according to a voltage potential of the select line.
9. The apparatus of claim 1 , wherein the magnetic junction comprises layers including: IrMn; CoFe; Ru; CoFeB; MgO; and CoFeB.
10. The apparatus of claim 1 , wherein the free magnetic layer with magneto-striction includes one of: CoFeB, FeGa, MnGa, or Terfenol.
11. The apparatus of claim 1 , wherein the first layer is a composite layer.
12. An apparatus comprising:
a transistor;
a conductive strain transfer layer coupled to the transistor; and
a Magnetic Tunnel Junction (MTJ) device having a free magnetic layer coupled to the conductive strain transfer layer, wherein the conductive strain transfer layer includes one of: W, Cu, Nb, or STO (StTiO 3 ).
13. The apparatus of claim 12 , wherein the transistor has a gate terminal coupled to a select line.
14. The apparatus of claim 12 , comprises
a piezoelectric layer coupled to the conductive strain transfer layer.
15. The apparatus of claim 14 comprises:
a first electrode coupled to the MTJ;
a second electrode coupled to the conductive strain transfer layer; and
a third electrode coupled to the piezoelectric layer.
16. The apparatus of claim 15 , wherein the transistor is coupled to the second electrode, and wherein the transistor is operable to electrically couple the source line to the second electrode according to a voltage potential of the select line.
17. The apparatus of claim 16 comprises another transistor coupled to the third electrode and the select line.
18. The apparatus of claim 12 , wherein the MTJ comprises layers of:
an electrode; anti-ferromagnetic layer; fixed magnet layer; exchange coupling layer; fixed magnet layer; tunnel oxide; and free magnetic layer with magneto-striction.
19. The apparatus of claim 12 , wherein the MTJ is formed with layers of: IrMn; CoFe; Ru; CoFeB; MgO; and CoFeB.
20. The apparatus of claim 12 , wherein the free magnetic layer with magneto-striction is formed from one of: CoFeB, FeGa, MnGa, or Terfenol.